1. Field of the Invention
The present invention relates to an inkjet printing head and an inkjet printer using the same. More particularly, the present invention relates to an inkjet printing head and an inkjet printer using the same including a nozzle unit having a length corresponding to the print medium, which can be various types of paper, transparencies, or other suitable medium for printing hard copies of data.
2. Description of Related Art
In general, an inkjet printer refers to an image forming device in which an ink is sprayed from an inkjet printing head, which is separated from an upper surface of a sheet of paper, and reciprocating in a paper moving direction and a direction perpendicular thereto. Recently, instead of the inkjet printing head reciprocating in a direction of the paper width, an inkjet printing head (also called, a line printing head) including a nozzle unit with a main scanning direction length corresponding to the paper width is used to achieve high-speed printing. In the above inkjet printer, the inkjet printing head is fixed so that only the paper is moved. Thus, a driving device for the inkjet printer is simple and can be used to implement high-speed printing. In the above inkjet printer, the length of the nozzle unit is, for example, about 210 mm to correspond to A4 size paper, when a printing margin in the width direction is not considered. Commonly-assigned Korean Patent Application Laid-Open Nos. 2003-64835 and 2004-10731 disclose an example of the inkjet printing head described above, the entire contents of which are incorporated herein by reference.
The paper is moved while maintaining an interval with the nozzle unit of about 1 to 2 mm. To get a high quality printing image, the interval should be constant. Four nozzle columns ejecting cyan, magenta, yellow and blue colored inks in a subscanning direction, respectively, may be arranged in the line printing head, in particular, the nozzle unit for the line printing head available for color-printing. Therefore, the length of nozzle in the sub direction is several tens of millimeters, typically, about 50 mm or more. Accordingly, as the length of the nozzle unit in the subscanning direction becomes larger, it is more difficult to maintain the constant interval between the paper and the nozzle unit when the paper passes under the nozzle unit. In addition, the paper may contact the nozzle unit. Thus, the paper may be smudged, and furthermore, the nozzle unit may be contaminated due to paper debris.